Ultrasound-powered bovine bone protein hydrolysate-flaxseed gum emulsions: modulation of stability, interfacial properties, and curcumin bioaccessibility

Designing stable and functional emulsions using natural emulsifiers remains a key challenge in the food industry, particularly due to the limited interfacial activity and weak compatibility of protein–polysaccharide systems under conventional processing methods. In this study, we prepared bovine bone protein hydrolysate–flaxseed gum (BBPH–FG) composite emulsions using ultrasound-assisted technology to address these challenges and to improve emulsion stability, interfacial behavior, and curcumin delivery performance. Ultrasonic power (0–1000 W) had a significant effect on emulsion properties, with the optimal results obtained at 750 W. At this power level, the droplet size decreased to 11.74 μm, the polydispersity index (PDI) to 0.291, and the zeta potential reached − 19.66 mV, indicating enhanced electrostatic repulsion and homogeneity. At this level, the interfacial protein adsorption rate and interfacial protein concentration increased to 79.85 % and 36.12 mg/m 2 , forming a compact interfacial film that enhanced stability. After 25 days of storage, the 750 W-treated emulsions exhibited the lowest peroxide value (9.24 mg/L) and TBARS (1.25 mg/L), as well as the highest curcumin encapsulation efficiency (82.1 %) and bioaccessibility (71.37 %). This study demonstrates that moderate ultrasound power facilitates the molecular rearrangement and synergistic interaction of BBPH and FG, thereby enhancing emulsion functionality and providing a promising strategy for developing polysaccharide-based delivery systems.